I don't have a 4:3 screen, but it seems to me like LibreRetro cores shouldn't be an issue at all. Perhaps only saving the config and overwriting the existing one may be a bit tricky ...
Engaging Integer scaler and setting the aspect ratio to custom you can easily set custom aspect ratio height and width. Here is an example of a custom 608x448 aspect ratio 2x (first image) and below 304x224 (1x).
Here is the 1x :
If you turn off the integer scaler the entire rendered image should 'stick' to the top-left of your display. From there you can set the Aspect ratio width and height so that it works for your monitor. You can then use X/Y Aspect ratio position settings to center the image... in example, below is a screenshot of a custom 820x720 aspect ratio centered by adjusting X pos to 230.
Now, when you've got a setup that works well on your screen you'll want to save it (main menu -> configurations -> save new configuration). It will save to:
You want to use the values in this config to overwrite the default retroarch cfg that is used. After saving your .cfg, just follow these instructions from point 5 onward.
Engaging Integer scaler and setting the aspect ratio to custom you can easily set custom aspect ratio height and width. Here is an example of a custom 608x448 aspect ratio 2x (first image) and below 304x224 (1x).
Here is the 1x :
If you turn off the integer scaler the entire rendered image should 'stick' to the top-left of your display. From there you can set the Aspect ratio width and height so that it works for your monitor. You can then use X/Y Aspect ratio position settings to center the image... in example, below is a screenshot of a custom 820x720 aspect ratio centered by adjusting X pos to 230.
Now, when you've got a setup that works well on your screen you'll want to save it (main menu -> configurations -> save new configuration). It will save to:
Code:
/recalbox/share/system/.config/retroarch/config/name_of_cfg.cfg
You want to use the values in this config to overwrite the default retroarch cfg that is used. After saving your .cfg, just follow these instructions from point 5 onward.